Benzthiazyl azo dyes



Patented June 15, 1948 2,443,314 BENZTHIAZYL AZO DYES Norman Hulton Haddock, Blackley, Manchester,

England, assignor to Imperial Chemical Industries Limited, a corporation of Great Britain No Drawing. Original application May 22, 1942,

Serial No. 444,108. Divided and this application December 14, 1944, Serial No. 568,201. In Great Britain June 16, 1941 Claims.

The present invention relates to the manufacture oi dyestuffs and intermediates therefor.

This application is a divisional from U. S. Serial No. 444,108, now U. S. Patent 2,368,657.

According to the invention we cause a p:p'- di B-methylbenzthiazyl) azobenzene disulphonyl chloride (made as described below) to interact with a thiocyanoarylamine or an N-mono-alkyl or -aralkyl thiocyanoarylamine of the benzene series, thereby obtaining the corresponding di (thiocyanosulphonarylamide) The invention also comprises the steps of hydrolysing a p:p'-di(G-methylbenzthiazyl) -azobenzene-d1(thiocyanosulphonarylamide) obtain- .ed in the above manner, to the corresponding p:p' di(6 methylbenzthiazyl) azobenzene di- (mercaptosulphonarylamide) and oxidising the latter to the corresponding polydisulphide.

The present polydisulphides represent sulphur-containing dyestufi's which may be applied to celluloslc material from sodium sulphide solution according to the usual practice with sulphur dyestuffs. By this means there are obtained bright orange-yellow shades possessing excellent fastness to severe washing, chemick and light.

The di(thiocyanosulphonarylamide) derivatives of p p-di(6-methylbenzthiazyl) azobenzene referred to above, not only constitute intermediates in the described manufacture of sulphur-containing dyestuffs, but may themselves be applied to cellulosic material from sodium sulphide solution according to the usual practice with sulphur dyestufis. By this procedure the di(thiocyanosulphonarylamide) derivatives become hydrolysed in the sodium sulphide solution to the corresponding =di(mercaptosulphonarylamide) derivatives. The latter subsequently become oxidised to polydisulphides on the fibre. Thus by the dyeing technique commonly employed with sulphur dyestuffs there are produced on the fibre the sulphur dyestuffs, to the production in substance of which the above-mentioned processes relate. In this way also, dyeings are obtained having the properties already described.

Accordingly, this invention is to be regarded as relating not only to the manufacture by the aforesaid processes of sulphur-containing dyestuffs in substance, but also to their production on the fibre, that is, on the cellulosic material directly, by employing in the technique usual in dyeing with sulphur dyestuffs, the above intermediate products, namely the di(thiocyanosulphonaryl-' amide) derivatives of p:p'-di(6-methylbenzthiazyl) azobenzene. I

The starting material which is a p:p-di(6- methylbenzthiazyl)azobenzene disulphonyl chloride, is made by treating with phosphorus pentachloride in a solvent such as benzene or o-dichlorbenzene (preferably above 140 C.) one of two disulphonic acids of pzp' di-(S-methfibenzthiazyl) azobenzene which are obtained (1) by sulphonating pzp di 6-methylbenzthiazyD azobenzene and (2) oxidising dehydrothio-p-toluidine sulphonic acid with, for instance, sodium hypochlorite. (This latter disulphonic acid is the dyestuff Chlorazol Fast Yellow B, Colour Index No. 814, and is given the constitution: p:p-di(6- methylbenzthiazyl) azobenzene-o: o -disulphonic acid). The disulphonyl chloride derivatives used as starting materials are accordingly two in num her and differ in constitution in respect of the p0- sitions occupied by the disulphonyl chloride groups which positions depend on whether the corresponding disulphonic acid is made (see above) process (1) or (2).

As thiocyanoarylamines or N-mono-alkyl or -aralkyl thiocyanoarylamines of the benzene series there may be used, for instance, p-thiocyano- N-methylaniline, p-thiocyanoaniline, p-thiocyanoo-aminoanisole, 2 :5-dich1oro-4-thiocyanoaniline or p-thiocyano-N-benzylaniline.

The invention is illustrated :by but not confined to the following examples in which the parts are by weight.

Example 1 10 parts of p:p'-di(6-methylbenzthiazyl) azobenzene disulphonyl chloride (prepared as below) are added to 30 parts of molten p-thiocyano-N- methylaniline and the mixture stirred at 135-140" C. for 3 hours. After cooling to C. 60-70 parts of alcohol are added and the orange precipitate is filtered and washed with alcohol. 11 parts of ptp di (6 -methylbenzthiazyl) azobenzene-di(N-- methyl 4 thiocyanosulphonanilide) are obtained.

The above product is dissolved in parts of boiling alcohol containing 20 parts of sodium sulphide crystals. Hydrolysis of the di(N-methyl-4-thiocyanosulphonanilide) derivative to the corresponding di(N-methyl-4-mercaptosulphonanilide) occurs. The solution is cooled, diluted with 300 parts of water. A stream of air is passed through. The di(N-methylmercaptosulphonanilide) becomes oxidised thereby to the corresponding polydisulphide which is thrown down as a precipitate. The precipitate is filtered off and dried. It forms a dark brown powder, soluble in concentrated sulphuric acid to give a bright orange-red solution, and in boiling aqueous sodium sulphide to an orange solution. Cotton is dyed from the latter in shades which after oxidising in the air are bright yellow, and possess excellent fastness to severe washing, chemick and good fastne ss to light.

The p:p'-di(G-methyibenzthiazyl) azobenzene disulphonyl chloride used above is prepared as follows: 12 parts of Chlorazol Fast Yellow B (Colour Index No. 814) 15 parts of phosphoruspender, soluble in hot organic solvents to give bright yellow solutions.

Example 2 parts of p:p-di(S-methylbenzthiazyl azobenzene disulphonyl chloride (made as described in Example 1) 5 parts of p-thiocyanoaniline and parts of dry nitrobenzene are heated together with stirring at 11'0120 C. for 2 hours. The resulting melt is poured into alcohol. The precipitate so formed is filtered and washed well with alcohol. The product, p:p'-di(6-methylbenzthiazyl) azobenzene di(4-thiocyanosulphonanillde) which is a yellowish brown powder, is boiled for hour with 50 parts of alcohol and 5parts of sodium sulphide crystals, 2. brownish-yellow solution of the :disodium salt of the corresponding p: p -.di S-rnethylbenzthiazyl) azobenzene di (mercaptosulphonanilide) being'obtained. This is d;- luted with water, and oxidised by the addition of sodium m'-nitrobenzene sulphonate at the boil until no more precipitation of the polydisulphide occurs. The bright yellow suspension is filtered, washed with water and. dried. This yellow powder dissolves in dilute sodium sulphidesolution, from which cotton is dyed in brownish-yellow shades, which on oxidising in air, become bright yellow.

Example 3 10 parts of pzp-di(-6-methylbenzthiazyl) 'azobenzene disulphonyl chloride (made as described in Example 1), 10 parts of 2-methoXy-4-thiocyanoaniline and 25 parts of dry nitrobenzene are heated together, with stirring, at 130 C. for 2 hours. The mixture is diluted with 100 parts of ethanol and the brownish-yellow precipitate filtered ofi and washed with ethanol and water.

The so-iobtained p:p-di(6-methylbenzthiazyl) azobenzene di(Z-methoxy-4-thiocyanosulphon anilide) is hydrolyzed by boiling with 100 parts of ethanol and 10 parts of sodium sulphide crystals for A, hour'to the corresponding di(2-methoxy 4 mercaptosulphonanilide). The clear brown solution of the sodium salt of the latter compound is diluted with 500 parts of water and oxidised to the corresponding .polydisulphide either (a) by addition of sodium m-nitrobenzene sulphonate at the boil as in Example 2 or .(b) by aeration in the cold as in Example 1. The polydisulphideis filtered ofi, washed and dried.

Bothlthe polydisulphide and the di(2-methoxy- 4-thiocyanosulphonanilide) dye cotton from aqueous. sodium sulphide solutions in brownish yellow'shades which on oxidising in the air become'bright yellow. The shadespossess very good fastness to severe-washing. chemick and good fastness to light.

Example 4 '5 parts of "p:p -di(fi-methylbenzthiazyl)azobenzene disulphonyl chloride (made as in Example 1), and 10 parts of 2:5-dichloro-4-thiocyanoaniline are heated with stirring at 135 C. for 2 /2 hours. The dark coloured mixture'is cooled to Slit-100C. and treated with 100 parts of ethanol. The'brownish-yellow precipitate of pipdiw-methylbenzthiazyl)azobenzenedi(2 :'5--.dichloro-l .thiocyanosulphonanilide) is filtered off, i

washedwith ethanol and water and dried. The ellow powder dissolves readily in boiling aqueous sodium sulphine solution containing a little cellosolve, from which solution cotton is dyed in shadeswhich after oxidation in the air, are yellow and possess very good fastness to severe washing chemick and good iastness to light.

Example 5 5 parts of p:p-di(6methylbenzthiazyl)azobenzene disulphonyl chloride (made as in Example 1), 10 parts of p-thiocyano-N-benzylaniline and 18 parts of dry nitrobenzene are heated with stirring at 130-135 C. for one and a half hours. The dark coloured mixture is cooled to about C. and treated with parts of ethanol. The brown solid p:p'-di(6-methylbenzthiazyl) azobenzene -di(N-benzyll-thiocyanosulphonanilide) is filtered off and washed with ethanol and water. 7

The above product is hydrolyzed by boiling with 100 parts of ethanol containing 10 parts of sodium sulphide crystals to the corresponding di(N- benZyl-4=-mercaptosulphonanilide). The clear brown solution of the latter compound is then oxidised to the corresponding polydisulphide by the addition of sodium m-nitrobenzene sulphonate at the boil as in Example 2. The yellow precipitate of polydisulphide is filtered off, washed and dried. It dyes cotton (with air oxidation) in yellow shades of-very good fastness properties from boiling dilute sodium sulphide solutions.

Example 6 5 parts of p:p-di(6-methylbenzthiazyl-azobenzene disulphonyl chloride (made as described below), 10 parts of p-thiocyanoaniline and .18

parts of. nitrobenzene are heated with stirring at -135 C. for 1 /2 hours. After cooling to 96- 100 (3., 200 parts of ethanol are added and the yellow p:p'-di(6 -1nethylbenzthiazyl) azobenzene di(4-thiocyanosulphonanilide) filtered off and washed with ethanol.

The above di(4 thiocyanosulphonanilide) hydrolysed by boiling with 50 parts of ethanol and 5 .parts of sodium sulphide crystals iorI hour to the corresponding di( l-mercaptosulphonanilide). tion of sodium nitrobenzene sulphonate at'the boil the corresponding polydisulphide is obtained follows: v10 parts of p:p'-di(6-methylbenzthi azyl)azobenzene are added to 65 parts of 20%, oleumduring 10 minutes with stirringat 25"- .C.

Stirring is continued for 5 minutes and 10v parts of 65% oleum are added. The sulphonation mixture is stirred at 25 C. until a sample .is.

.readily and completely soluble in dilute ammonia (onshakingfor 10-,15 minutes) and poured .on

to ice. The yellow precipitate of the sulphonic acid'isfiltered oif, washedwith salt solution until iree'from acid and dried. 15 partsof this-suiphonic acid (passed through 100 mesh;sieve).,.-'100 parts of phosphorus pentachloride and 25 parts of phosphorus oxychloride are heated with stirring inan oil bath at 161-165 C. for .3 hours, After cooling overnighhthepasty massis added u gradually to crushed ice, The precipitatedgsul- By oxidising the latter. by the. addi parts of p:p-di(G-methylbenzthiazyl)azobenzene disulphonchloride (made as described in Example 6), parts of pthiocyano-N- methylaniline and 18 parts of dry nitrobenzene are heated at 130-135 C. for 1 /2 hours. The mixture is diluted with 200 parts of ethanol and the yellow solid (p:p-di(G-methylbenzthiazyl) azobenzene di(N methyl -4-thiocyanosulphonanilide)) filtered off and Washed with ethanol and water.

The di(N-methyl-4-thiocyanosulphonanilide) is hydrolysed by boiling with 50 parts of ethanol and 5 parts of sodium sulphide crystals for hour to the corresponding mercapto compound. After dilution with 500 parts of water, the solution is oxidised with sodium m-nitrobenzene sulphonate at the boil (as in Example 2). The precipitated polydisulphide is filtered off, washed and dried. It is a yellow-brown powder, readily soluble in aqueous sodium sulphide, from which solution cotton is dyed in yellow shades, which become brighter on oxidation in the air and have good fastness properties.

Example 8 5 parts of p:p'-di(S-methylbenzthiazyl)azobenzene disulphonyl chloride (made as described in Example 6), 10 parts of p-thiocyano-N-benzylaniline and 18 parts of dry nitrobenzene are heated in an oil bath at 130-135" C. for 1 hours. The dark coloured mixture after cooling to 90-100 C. is treated with 20 parts of ethanol and the brown precipitate (the N-benzyl- 4 thiocyanosulphonanilide) filtered oil and Washed with ethanol and water. It is hydrolysed to the corresponding mercapto compound and the latter oxidised to the polydisulphide as described in Example 5. The polydisulphide dyes cotton from solution in aqueous sodium sulphide in yellow shades of very good fastness to severe washing, chemick and good fastness to light.

Ewample 9 5 parts of p:p-di(6-methylbenzthiazyl)azobenzene sulphonchloride (made as described in Example 6), 7 parts of 2-methoxy-i-thiocyanoaniline and 18 parts of dry nitrobenzene are heated at 125-130 C. for 2 hours and then at 135-140 C. for hour. After cooling, the melt is treated with 200 parts of ethanol and the brownish-yellow precipitate filtered off 'and washed with ethanol and water.

The above product (p:p'-di(6-methylbenzthiazyl) azobenzene-di(2-methoxy-4-thiocyanosulphonanilide)) is hydrolysed to the corresponding mercapto compound and oxidised to the polydisulphide as described in Example 3. It dissolves readily in boiling dilute aqueous sodium sulphide from which solution cotton is dyed in yellow shades of very good fastness properties.

I claim:

1. A solution of a p:p'-di-(6-methylbenzthiazyl) derivative made by hydrolyzing a pZp'-di- (6-methylbenzthiazyl) azobenzene-bis (N-substituted-4-thiocyanosulfonanilide) by heating the same in solution in which a crystalline alkali metal sulfide is dissolved, until a solution of the.

6 corresponding alkali metal bis-(N-substituted-elmercaptosulfonanilide) is formed, said N-substitutedl-thiocyanosulfonanilide group being represented by the formula in which R. is one of the group consisting of hydrogen, alkyl and benzyl; and R is from the group consisting of hydrogen, alkoxy and halogen.

2. A solution of a p:p'-di-(G-methylbenzthiazyl) derivative made by hydrolyzing p:p'-di-(6- methylbenzthiazyl azobenzene di (NH--thiocyanosulfonanilide) by heating the same in solution in which a crystalline alkali metal sulfide is dissolved, until a solution of the corresponding alkali metal bis-(NH- l-mercaptosulfonanilide) is formed.

3. A solution of a p:p'-di-(B-methylbenzthiazyl) derivative made by hydrolyzing p:p-di-(6- methylbenzthiazyl) azobenzene-di-(N-methyl-lthiocyanosulfonanilide) by heating the same in solution in which a crystalline alkali metal sulfide is dissolved, until a solution of the corresponding alkali metal bis-(N-methyll-mercaptosulfonanilide) is formed.

a. A. solution of a p:p'-di-(6-methylbenzthiazyl) derivative made by hydrolyzing p:p-di-(6- methylbenzthiazyl) azobenzene-di-(N-benzyl-4- thiocyanosulfonanilide) by heating the same in solution in which a crystalline alkali metal sulfide is dissolved, until a solution of the corresponding alkali metal bis-(N-benzyl-4-mercaptosulfonanilide) is formed.

5. The process of making a p, p (fi-methylbenzthiazyl) azobenzene di(mercapto-sulfonarylamide) which comprises reacting with heating a p,p' di(6 methylbenzthiazyl) -azobenzene-disulfonyl chloride and a thiocyanoarylamine of the benzene series represented by the formula in which R is one of the group consisting of hydrogen, alkyl and benZyl and R is from the group consisting of hydrogen, alkoxy and halogen, until the chlorine of said p,p-di(6-methyl-benzthiazyl) -azobenzene-disulfonyl chloride is replaced by the thiocyanoarylamine group, and then hydrolyzing the p,p-di(S-methyl-benzthiazyD-azobenzene derivative thus formed in the presence of a sulfide of an alkali metal for transforming the resulting thiocyanoarylamine group to the corresponding mercapto-sulfonanilide group.

NORMAN HULTON HADDOCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,368,658 Haddock Feb. 6, 1945 FOREIGN PATENTS Number Country Date 16,708 Great Britain 1893 Certificate of Correction Patent No. 2,443,314.

NORMAN HULTON HADDOOK It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 4, line 3, for sulphine read sulphide; column 5, line 36, for 20 parts read 200 parts; column 6, line 15, after methylbenzthiazyl insert a closing parenthesis; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 17th day of August, A. D. 1948.

THOMAS F. MURPHY,

Am'atant Oommz'mhser of Patents.

June 15, 1948. 

